A machining time-estimating method for a wire electrical discharge machine for estimating the remaining machining time (Tr) during the machining of a workpiece comprises: a step for setting a predicted machining velocity; a step for determining the actual machining velocity; a step for determining an estimated machining velocity so as to incorporate the predicted machining velocity and the actual machining velocity at a specified ratio, that is, a reference ratio; and a step for calculating remaining machining time from the estimated machining velocity. By executing the actual machining velocity-determining step to the remaining machining time-calculating step repeatedly to estimate remaining machining time moment by moment, remaining wire electrical discharge machining time is estimated with reduced error.

A machining time-estimating method for a wire electrical discharge machine for estimating the remaining machining time (Tr) during the machining of a workpiece comprises: a step for setting a predicted machining velocity; a step for determining the actual machining velocity; a step for determining an estimated machining velocity so as to incorporate the predicted machining velocity and the actual machining velocity at a specified ratio, that is, a reference ratio; and a step for calculating remaining machining time from the estimated machining velocity. By executing the actual machining velocity-determining step to the remaining machining time-calculating step repeatedly to estimate remaining machining time moment by moment, remaining wire electrical discharge machining time is estimated with reduced error.

In a wire electric discharge machine, time from application of a voltage to a machining gap between a workpiece and a wire electrode until occurrence of electric discharge is measured as a discharge delay time, and the measured discharge delay time is integrated over a predetermined measurement period to calculate a discharge delay integrated time. Further, the number of times of the voltage application in the measurement period is counted. An average discharge delay time per voltage application in the measurement period is calculated from the discharge delay integrated time and the number of times of voltage application. The movement of the wire electrode with respect to the workpiece is controlled on the basis of the average discharge delay time.

In a wire electric discharge machine, time from application of a voltage to a machining gap between a workpiece and a wire electrode until occurrence of electric discharge is measured as a discharge delay time, and the measured discharge delay time is integrated over a predetermined measurement period to calculate a discharge delay integrated time. Further, the number of times of the voltage application in the measurement period is counted. An average discharge delay time per voltage application in the measurement period is calculated from the discharge delay integrated time and the number of times of voltage application. The movement of the wire electrode with respect to the workpiece is controlled on the basis of the average discharge delay time.

A device for machining a part (8) by electrical discharge machining using an electrode wire (4), comprising: means (20, 30, 60) for holding the electrode wire (4) taut and driving it to translate longitudinally, in proximity to said part (8) to be machined, in a sparking zone (5), means (50) for making a stream of dielectric liquid flow through the sparking zone (5) between the electrode wire (4) and the part (8) to be machined, an electrical power source (10) for generating electrical pulses that cause sparks in the sparking zone (5) between the electrode wire (4) and the part (8) to be machined, controlling means (40) that control the device depending on the machining parameters, measuring means (70) for evaluating the quantity of gas bubbles present in the sparking zone (5) between the electrode wire (4) and the part (8) to be machined, and for delivering to the controlling means (40) a signal (73) representative of said quantity of gas bubbles, in the controlling means (40), adapting means (41) for modifying the machining parameters, so as to maintain the value of said signal (73) within a suitable range of signal values.

The object of the present invention is to make it possible to maintain a stable electric discharge and to achieve a stable quality and machining performance even when a work having a non-uniform composition is machined. A wire electric discharge machining device performs electric discharge machining on a work while controlling an inter-electrode distance between a wire and the work based on an inter-electrode voltage between the wire and the work so as to match a set target voltage. The wire electric discharge machining device includes an inter-electrode voltage measuring unit that measures the inter-electrode voltage, an actual amplitude calculating unit that calculates an amplitude of the measured inter-electrode voltage, and a target voltage correcting unit that corrects the target voltage in such a way that the calculated amplitude approaches the target amplitude that is set to a value larger than zero.

The object of the present invention is to make it possible to maintain a stable electric discharge and to achieve a stable quality and machining performance even when a work having a non-uniform composition is machined. A wire electric discharge machining device performs electric discharge machining on a work while controlling an inter-electrode distance between a wire and the work based on an inter-electrode voltage between the wire and the work so as to match a set target voltage. The wire electric discharge machining device includes an inter-electrode voltage measuring unit that measures the inter-electrode voltage, an actual amplitude calculating unit that calculates an amplitude of the measured inter-electrode voltage, and a target voltage correcting unit that corrects the target voltage in such a way that the calculated amplitude approaches the target amplitude that is set to a value larger than zero.

A wire electric discharge machine provided with a disconnection repairing unit includes a core-fixing-end-position storing unit for storing a core fixing end position of a depositing and accumulating operation machined most lately among positions at which the depositing and accumulating operation for machining wastes by a core fixing function ends in a machining shape currently being machined and a disconnection repairing unit for executing automatic connection between a disconnection position and the core fixing end position.

Whether or not an inter-electrode voltage exceeds a voltage threshold is determined after a predetermined inter-electrode state determination period has passed since application of an induction voltage (inter-electrode voltage) to an inter-electrode gap. Thus, an inter-electrode gap amount between a wire electrode and a work is estimated. A pause time during which electrical discharge is not performed is changed according to an estimation result of the inter-electrode gap amount.

Whether or not an inter-electrode voltage exceeds a voltage threshold is determined after a predetermined inter-electrode state determination period has passed since application of an induction voltage (inter-electrode voltage) to an inter-electrode gap. Thus, an inter-electrode gap amount between a wire electrode and a work is estimated. A pause time during which electrical discharge is not performed is changed according to an estimation result of the inter-electrode gap amount.